Which is the best fast-work easy method for inserting components & solder ?

Soldering by hand (holding iron by right hand & soldering wire by left) is one of the most time consuming & chances for bridging two points. I have to always check carefully by DMM connectivity. Another problem, after inserting components, I turn to solder side to solder, component drop down. I can't use adhesive because I may want to remove component for any reason. I have seen branded systems & their PCB, it looks clean & neatly soldered.

I think about FOUNTAIN PEN which can drop required ink to write well. Similarly FOUNTAIN PEN having soldering material (tin) instead of Ink. Where-ever I want to solder I just touch the pen tip, it drop required tin and get soldered ( Please don't laugh )

For DIY purpose I can't buy expensive machines. I want to know, how this job handled by expert members?

Practice I'm afraid. As for holding components in place, once inserted, bend the legs slightly out so they don't fall back through the holes.

__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?

As others have said, smallest components first, and bend the legs a bit.

For larger things like electrolytics, I usually hold it in place with my fingers and quickly dab a touch of solder to one leg with the iron, then properly solder the second leg. After that I go back and properly solder the first leg.